The disclosure of Japanese Patent Application No. Hei 9-156544 filed on Jun. 13, 1997 including the specification, drawings and abstract is incorporated herein by reference in its entirety.
1. Field of Invention
The present invention relates to a touch operation information output device which outputs touch operation information by optically detecting a touch range with respect to an operating surface.
2. Description of Related Art
Conventionally, vehicles, for example, are provided with a display device with a touch operation function. One example of this kind of display device is structured to detect a finger touching a position with respect to a display screen through an optical sensor.
Specifically, light projection elements and light-receiving elements are arranged so as to form a plurality of parallel optical axes corresponding to a vertical direction and a horizontal direction of the display screen. Based on the fact that the optical axes which go through a projection element to a light-receiving element are cut by a finger touching the display screen, the display device is structured to detect the center position of the touched area and to output the coordinate data thereof.
Accordingly, for example, when a screen for an air conditioner is displayed, the air conditioning in the vehicle can be arbitrarily adjusted by touch-operating the button display part which is displayed a screen. By using this kind of display device with a touch operation function, the manual vehicle switches, such as for the air conditioner, audio and car navigation system, etc., can be omitted. Therefore, the instrument panel can look neat.
However, when the above-mentioned display device with the optical type touch operation function is provided, there are cases when bright sunlight is incident upon the display device. In this case, even though the light-receiving element is shielded by a finger, there is a tendency for the detection of the touch operation to become unreliable because the sunlight causes the light-receiving element to be in a light-receiving condition.
Moreover, when dust collects on the display screen, the optical axis may be shielded by the dust. In this case, the detection of the touch operation with respect to the display screen becomes unreliable.
The invention provides a touch operation information output device which can detect a touch operation on a operating surface, despite the influence of light or the existence of obstructions, and output reliable touch operation information.
The invention includes a plurality of light projection elements and light-receiving elements to form a vertical direction optical axis group and a horizontal direction optical axis group that are composed of a plurality of parallel optical axes in the vertical direction and the horizontal direction on the operating surface, and outputs touch operation information to the operation surface based on a light-shielding condition of each of the optical axis groups. A light-shielding member is provided to shield the front surface of the light-receiving elements from the light, and has an aperture to form an optical axis only between light projection elements that are opposed to the light-receiving element. A matte (or non-reflective) light-shielding slit member is provided along the operating surface in the aforementioned aperture of this light-shielding member, and divides the inside of the aperture.
In this structure, when the operating surface is touched, the optical axis corresponding to the portion which is touched by the operating surface becomes light-shielded. The corresponding touch position on the operating surface can be confirmed by an external machine that outputs the desired data.
Since the light-shielding member is provided in front of the light-receiving elements for forming the optical axes, and since the apertures for forming the optical axes are provided only between the light projection elements that are opposed to the light-shielding member, the influence by the interference light which is incident from the adjacent optical axis to the light-receiving element, can be prevented.
Moreover, even if sunlight is incident to the apertures of the light-shielding member, inside the aperture, a light-shielding slit member which divides the inside of the aperture along the operating surface, is provided. The sunlight which is incident to the aperture is absorbed by the slit member, thus any sunlight which may be incident to the aperture parts and reflected in the aperture, can be prevented from reaching the light-receiving elements.
In the above-mentioned structure, it is also appropriate to form a concave part along the optical axis in the inside bottom surface of the apertures of the light-shielding member. According to this kind of the structure, even when incidental sunlight reaches the inside bottom surface of the apertures, since the concave part is formed along the optical axis in the inside bottom surface, and since sunlight is absorbed at the light-shielding slit member, incidental sunlight can be prevented from affecting the light-receiving elements.
The invention arranges a plurality of light projection elements and light-receiving elements to form a vertical direction optical axis group and a horizontal direction optical axis group that are composed of a plurality of parallel optical axes in a vertical direction and a horizontal direction on an operating surface. The touch operation information output device is provided with an output device that outputs touch information to the operating surface when it is determined, based on a light shaded condition of each optical axis, that a touch operation has occurred. The light projection elements and light-receiving elements that form the optical axis groups are alternately arranged the direction of an optical axis from one of the light projection elements to one of the light-receiving elements is different than the direction of an adjacent optical axis. In addition, when an optical axis is alternately in the light-receiving condition in the optical axis group, the optical axis is considered to be a light-shielded optical axis.
According to this kind of structure, since the projection element is arranged right next to the light-receiving element, the light-receiving element receives the light from the adjacent projection element, and any occurring interference can be prevented.
In this case, a plurality of the light-receiving elements that are arranged on one side, become the light-receiving because of the influence of sunlight, even through the light-receiving elements should be in the non-light-receiving condition due to a touch operation on the operating face. However, since a plurality of the light-receiving elements that on the other side are in the non-light-receiving condition due to the touch operation on the operating surface, when a intermittent light-shielded optical axis group exists in the optical axis group in which the optical axis is alternately in the light-receiving and non-light-receiving conditions, the optical axis is considered as a light-shielded optical axis, so that the output device reliable detects the touch position of the operating surface and outputs without being influenced by the sunlight.
The invention arranges a plurality of light projection elements and light-receiving elements to form a vertical direction optical axis group and a horizontal direction optical axis group that are composed of a plurality of parallel optical axes in a vertical direction and a horizontal direction on an operating surface. The touch operation information output device is provided with an output device that outputs touch operation information to the operating surface when it is determined, based on a light shaded condition of each optical axis, that a touch operation has occurred. The output device determines whether a touch operation has been performed when a plurality of light-shielded optical axes exist in the optical group, when these light-shielded optical axes continue to be light-shielded, and the number of these light-shielded optical axes is a predetermined number. The output device may also determine whether a touch operation is performed when these light-shielded optical axes shift, the number of the optical axes that are included in a maximum width from a first light-shielded optical axis to a last light-shielded optical axis is a predetermined number, and when a number of light-entering optical axes that are included in the maximum width is a predetermined number.
According to this kind of structure, when a plurality of optical axes continue to be shielded by a finger touching the operating surface, and the number of these light-shielded optical axes becomes a predetermined number corresponding to the size of a finger, the output device evaluates that the operating surface is touch-operated, and can output the touch position with respect to the operating surface by outputting the coordinate data which shows the center position of the light-shielding optical axis group.
In addition, when light-receiving elements which originally should be in a non-light-receiving element condition due to the finger touch operation, are in a light-receiving condition due to the incidental influence of light, or the like, a touch operation on the operating face may not be detected. However, when the light-shielded optical axis exists by shifting the light-entering optical axis, the number of optical axes which are included in the maximum width from the first light-shielded optical axis to the last light-shielded optical axis is a predetermined number, and when the number of light-entering optical axes which are included in that maximum width is less than the predetermined number, the output device evaluates that it is a touch operation on the operating surface, and outputs the coordinate data which shows the center position of the maximum width. By doing this, the coordinate data which shows the center position of the touch operation can be output without being influenced by the incidental light, or the like.
In the invention, when the output device evaluates that the touch operation has not been performed even though a plurality of light-shielded optical axis exist in the optical axes group, the evaluation of the touch operation is re-executed with the condition of removing the light-shielding optical axis that has not shifted, from the previous detection time.
According to this kind of structure, when a touch operation is performed when the light-shielding optical axis exists because dust, or the like, existing on the operating surface, the maximum width which is from the light-shielding optical axis to the last light-shielding optical axis becomes larger than the width corresponding to a finger, therefore, even through the touch-operation is performed, the output device may determine that the touch operation has not been performed. However, when the output device determines that the touch-operation has not been performed when a plurality of light-shielding optical axis exist in the optical group, since the evaluation of the touch operation is re-executed after removing the light-shielding optical axis which has not shifted from the previous detection time, the touch-operation position is reliably detected by invalidating the existence of the light-shielded optical axis obstructed by dust, or the like.